<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>

        div .c1{
            color:red;
        }

        .c1 .c2 .c3{
            color:green;
        }


        #d1{
            color:yellow;
        }

        div{
            color:green;
        }

        .c2{
            color:red;
        }

        .c3 a{
            color:red;
        }

    </style>
</head>
<body>

<div class="c2">
    霜叶红于二月花
    <div class="c1" id="d1" style="color:blue;">
<!--    <div class="c1">-->
        停车坐爱枫林晚
    </div>
</div>



<div class="c3">
    <a href="">百度</a>
</div>


</body>
</html>